Motor speed control apparatus for steel slitting machine



H. B. HOLLIS May 25, 1965 MOTOR SPEED CONTROL APPARATUS FOR STEELSLITTING MACHINE Original Filed Aug. 24, 1962 2 Sheets-Sheet 1 VENTOR.KS HOLLIS M G .W

HUBERT BROO ATTQRNEY y 25, 1965 H- B. HOLLIS 3,185,908

MOTOR SPEED CONTROL APPARATUS FOR STEEL SLITTING MACHINE Original FiledAug. 24, 1962 2 Sheets-Sheet 2 INVENTOR. HUBERT BROOKS HOLLIS AT TOR NEYUnited States Patent MOTQR SPEED CONTROL APRARATUS FOR STEEL SLIT'IENGMACHINE Hubert Brooks Hollis, 717 W. Madison Ave., Montebello, Calif.Continuation of application Ser. No. 219,153, Aug. 24, 1962. Thisapplication Oct. 19, 1964, Ser. No. 406,658

Claims. (Cl. 318-6) This invention relates to speed control devices, andconcerns itself more particularly with apparatus for controlling thespeed of electric motors and the like; such as those employed as theprime mover for the coiler of steel slitting machines. This applicationis a continuation of pending application, Serial No. 219,153, filedAugust 24, 1962, and entitled Speed Control Apparatus for Steel SlittingMachine.

In the prior art, many speed control devices have been proposed forcontrolling the speed of electric motors used for driving conveyorbelts, continuous strips, recording and film tapes, and even fabricslitting machines, which have not been so in their adaptation to heavyindustry, such as sheet steel coiling.

Accordingly, it is a primary object of the instant invention to providean automatic speed control device for electric motors, and the like,which in turn accurately and effectively control the linear speed of alarge, heavy continuous strip such as sheet steel.

Another object of the invention is to provide a speed control device ofthe type described which is readily adaptable to existing manualcontrols without extensive alterations.

A further object of the invention is to provide a speed control deviceof the type described which is adaptable to existing manual controls,and which further provides the quick and easy selection of either manualor automatic control.

Other objects and advantages of the invention will become apparent asthe description proceeds, and a more comprehensive understanding of itwill be afforded from the following detailed description when consideredin conjunction with the accompanying drawings, in which like referencenumerals have been used in the different views to designate like parts,and in which:

FIGURES 1 and 2 are plan and side elevational views, respectively, of asteel slitting machine in conjunction with which the instant inventionmay be used by way of example;

FIGURE 3 is a cross-sectional view of a speed adjusting unit of thespeed control device of the instant invention illustrating itsadaptation to existing manual controls;

FIGURE 4 is a front view of the unit illustrated in FIGURE 3 taken alongthe line 4-4 thereof;

FIGURE 5 is a schematic diagram of the speed control device of thepresent invention showing all parts thereof; and

FIGURE 6 is a wiring diagram of the same illustrating the circuitry forthe electrical components thereof.

Although not intended to be limiting in any sense of the word, apreferred embodiment of the invention has been illustrated and will bedescribed in connection with its use for controlling the linear speed ofa continuous 3,185,908 Patented May 25, 1965 The slitting machine thusdescribed performs two functionsor operations on the continuous sheetsteel strip as it passes from the uncoiler 11 to the coiler 17. Firstly,it shot blasts the strip 20 to remove the scale and rust from both sidesthereof and, secondly, it slits it into a number of strips of smallerwidth and coils them into individual rolls such as 21, 22, 23 and 24.

To properly perform these functions it is necessary to move the sheetsteel through the machine at a continuous linear speed. However, thephysical characteristics of the material handled, and the machineitself, makes this very difiicult. Usually the roll of steel placed onuncoiler is as much as thick, four feet wide, 700 feet long, and weighsbetween nine and ten tons. This strip is slit into four strips which arewound on the coiler spindle 25 to form coils having an inside diameterof thirty inches, an outside diameter of sixty inches and weighs overtwo tons.

Further, the distance between the uncoiler and coiler is approximatelyeighty feet, and the entire motive power for the movement of the steelthrough the machine is supplied through the coiler 17, all of which makethe movement of the steel strip erratic. Moreover, this condition isfurther aggravated by the fact that the strip occasionally possesseswrinkles which, as they pass through the guide rolls of the machine,cause the strip to momentarily slow down and then surge forward. Obviousalso, is the fact that as the diameter of the coils on the coilerincreases, the linear speed of the strip increases. With theseconditions imposed, plus the additional requirement that the strip mustpass between the shot blast units at a uniform rate of speed to preventunder or over cleaning (pitting), it will be apparent that the speed ofthe strip through the machine is critical. Also, where productionstandards or incentive systems are'in effect, it is necessary to have afixed machine speed as a base upon which time study calculations can bemade.

Heretofore the problem of controlling the speed of the strip through themachine has been met by having an operator manually control the speed ofthe coiler motor at all times during the operation of the machine. Here,the operator is required to continuously observe the speed of the motoron a tachometer graduated to register the linear speed of the strip andmanually operate the coiler motor rheostat so as to maintain a constantspeed for the strip at, say, fifteen feet per minute. With the injectionof the human factor into this operation, overcontrolling of the motoroften results. The present invention meets all of the exactingrequirements of the aforestated problem and overcomes the deficiency oferratic overcontrol resulting from manual operation.

With reference to FIGURE 5 of the drawings, the speed control'apparatusof the instant invention, in a preferred embodiment thereof, comprises aspeed pick-up head, an electric timer, a relay switching device, and aspeed adjusting unit (FIGURES 3 and 4) designated, generally andrespectively, by the reference numerals 26, 27, 28 and 29. The pick-uphead 26 consists of a small rubbertired wheel 30 to which is attached aswitch operating cam 31 positioned to actuate a first limit switch 32and a second limit switch 33. The limit switch 32 is a single pole,single throw switch which is normally open, and switch 33 is of the sametype, but normally closed.

In the illustrated use of the apparatus of the present in vention, thepick-up head 26 is mounted on the upper shot blast unit 13 so as to haveits wheel 30 frictionally engage the steel strip 20. Here the diameterof the wheel 30 is chosen to translate the linear motion of the strip 20into rotary motion proportionate to the former. The timer 27 may takeany suitable form of those commercially avail- =3: able, such as anEagle Microfiex Timer, No. C-231, as may the relay 28 which is of thethree pole type, with two poles normally open and one pole normallyclosed.

As illustrated in FTGURES 3 and 4, the speed adjusting unit 29 iscontained in a housing 34, which may be attached to an existing speedadjusting device such as a rheostat 37 by conventional fastening meanssuch as screws or the like. A manual control knob 38 for the rheostat 37is mounted externally of the housing 34 for manual operation of theformer through means of a shaft 3?, which shaft by screws 36 isconnected to the rheostat as shown in FIGURE 3. Automatic movement ofrheostat 37 is effected by means of a reversible speed reducer motor 49through a gear box 41, a reduction gear 42, and clutch 43 splined to theshaft 39 and movably engageable with a gear wheel 44 of the reductiongear 12. The motor 40 may, for example, take the form of a Bodine speedreducer motor, Type NCl34R, manufactured by the Bodine Electric Company,of Chicago, Ill.

A clutch 43 is engaged with the gear wheel 44 by means of a clutchsolenoid acting through a clutch arm as, the former device being underthe control of a selector switch 47 operable externally of the housing34. A friction brake 48 (FIGURE 4) comprising two oak blocks 49 and 50which are adjustably spring-loaded by means of two butterfly bolt, nut,and spring assemblies 51 and 52, is provided to limit the overtravel ofthe rheostat 37 at the end of a correcting motion. Here, due to thelarge gear reduction between the motor 40 and shaft 39, the rheostat 37would coast past its proper setting if rotation of the shaft were notdampened by the brake 48. It is to be understood that a clutching orelectric brake could be substituted for the friction brake if desired.

For the sake of simple description and ease in tracing the circuits forthe apparatus as shown in FIGURES and 6, the conductors, lines, andcontacts of the various electrical components are designated by lettersand reference numerals depicting function. Thus, the control circuit isconnected to an electric supply, which may be 110 volts, by the lines L1and L2, and the connections with these lines at the contact points ofthe various components are similarly designated. A timing motor of thetimer 27 is designated M, and the contacts of the timer by the circledreference numerals as shown in FIGURE 5. Also, a conductor 59 connectsthe switch 33 to a normally open contact of the relay 28, and a line 64connects a normally closed contact of the relay to the reverse pole ofthe motor 4%. Additionally, the timer 27 is further designated TRI todifferentiate the same from its contact elements designated TRl-A, TRIB,and TRLC. Similarly, the relay 28 is further designated CR1 todifferentiate the same from its contacts CRT-A, CRT-B, and CRI-C. Allother components in FIGURES 5 and 6 are shown as previously designated.

In its preferred embodiment and illustrated application, the apparatuscontrols the speed of the motor 18, and consequently, the speed of thestrip 20 through the steel slitting machine. With the pick-up head 26mounted as shown in FIGURE 2, its pick-up wheel 3% is held in frictionalengagement with the strip 20 and is rotated by the movement of the stripthrough the machine. Here, by way of example only, it will be assumedthat for the correct speed of the strip, say fifteen feet per minute,the diameter of the wheel 30 is such that it will be caused to make onecomplete revolution in four seconds by the movement of the strip 20 atthis correct and desired speed. Assuming further that the limit switches32 and 33 are so mounted that their trips are located three-fourths of arevolution apart, and that the timer 27 (TRI) is set for three seconds,then, as the control cycle is initiated, the cam 31 on wheel Ed is movedto close the limit switch 32. This causes the relay 28 to close (CRT-Aand CRT-B to close, CRI-C to open) and lock itself in through L2, 59,and the normally closed switch 33. The closing of relay 28 (CRI-A)initiates the start of the timer 27 (TRI), and

if the strip 2t) is moving at less than its desired speed of fifteenfeet per minute, the following events will occur.

At the end of three seconds the cam 31 will not have moved far enough totrip the switch 33, and the timer 27 (TRI) will go into timed outposition (TRLC closes and both TRI-A and TRLB open), but will still beenergized from relay 28 (CRT-A). In this position, contacts 5658 oftimer 27 (TRLC) close, and send a signal to the motor 40 which in turnmoves the rheostat 37 to increase the speed of the motor 18, the coiler17 and lastly the steel strip 23. This circuit is traceable from L2, 59of the relay 28; 59, 56 of switch 33; and 56, 53 of timer 27 (TRI-C).

The signal just described continues to be sent until the pick-up wheel30 and its cam 31 rotates to open switch 33, thus opening the holdingcircuit for the relay 28 previously described. This in turn causes therelay 2% to drop out (CRLA and CRI-B open and CRLC closes), the timer 27is de-energized and returns to its ofl position, with the result thatthe motor 4t) ceases to advance. If, on the other hand, the strip 20 ismoving faster than its desired speed of fifteen feet per minute, thepick-up wheel 39 and its cam 3-1 will rotate to open switch 33 beforethe three-second timing interval of the timer 27, initiated as describedabove, is completed. Consequently, the relay 23 will drop out, but thetimer 2'7 (TRI) will continue timing, since it is held in by its ownholding circuit L2, 54 (TRi-A) through the jumper from 54 to 53.

A signal is then sent from L2, 54 (TRLA) through the jumper 54 to 53,and 53, se of (CRI-C) to reverse the motor 49, which through the samesequence of operations as described above for increase, decreases thespeed of the strip 20. The signal will continue until the timer 27 (TRI)has completed its three-second timing period and is returned to the offposition, at which time the motor 46! ceases its retarding motion.

As a third condition, if the strip 20 is moving at its correct anddesired rate of speed, fifteen feet per minute, the relay 28 and thetimer 27 will both trip out at the same instant and no corrective signalwill be sent to the motor 4%). Thus, it is seen that the rheostat 37 maybe considered as a controller for any prime mover, such as the motor 18,and that the motor 49 represents a signal responsive means. As such, thelatter receives a first signal through the timer switch TRI-C to advancethe motor 4% and a second signal through the relay switch CRT-C toretard the same, in which case TRIC may be considered a first switchingmeans and CRLC a second switching means, aside from the other similarelements of both employed to condition holding circuits.

Further, the switch 32 which closes momentarily to condition TRIC topass a first signal to the motor 40, and CRI-C to pass a second signalto the same upon drop out of CR1, may be considered as a third switchingmeans. Likewise, switch 33 may be considered as a fourth switchingmeans, and the wheel 39 and cam 31 as a rotatable switch operatingmeans. Broadly then, switch 32 which is normally opened, is closedmomentarily to initiate a time cycle for timer 27. This timer, aspreviously described, is conditioned to pass a signal to motor 40through TRI-C which closes when the timer ends the time cycle for whichit is set, defined as timed out position. Further, when the timer isde-energized it assumes its off position and passes no signal. Further,CRI-C which is normally closed, is locked open upon energization of CR1and closes upon drop out of the latter. TRI-A lOCks TRI (solenoid andmotor M) during the period the timer 27 is timing, and TRI-B normallyclosed, opens when timer 27 assumes its timed out position.

Neglecting the action of the holding circuits for the moment, whenswitch 32 closes by movement of the rotatable switch operating means303l, it conditions TRI-C to pass a first signal to motor 44) if timer27 reaches its timed out position before 30-31 opens normally closedswitch 33. Thereafter this signal will continue until switch 33 isopened. If switch 33 is opened by 3031 before the timer 27 has ended thetime cycle for which it is set, then a second Signal is passed to motor40 through CRI-C which moves to its normally closed position whennormally closed switch 33 is opened and relay 28 drops out. This signalwill continue to be passed by virtue of the fact that TRI is locked inby TRLA until the timer completes its time cycle and returns to its offposition. If switch 33 is opened in sequence after the switch 32 ismomentarily closed at the same instant the timer 27 has ended the timecycle for which it is set, the latter is de-energized and CRI drops outso that neither a first nor a second signal can be passed to motor 40,and so long as this condition exists, the motor 18 will be operating atits desired speed. If it slows down, the first signal will be sent tomotor at), and rheostat 37 will be turned to increase the speed of motor18; if it runs too fast, the second signal is sent to the motor 40, andrheostat 37 is turned to decrease the speed of motor 18, the speed ofthe sheet steel strip is increased or decreased, and the speed of travelof 3t)31 is increased or decreased to close the control cycle.

While the normal correct speed for the strip 20 may be fifteen feet perminute, it may be desirable to slow its speed to ten feet per minute fordirtier steel or to increase the speed to twenty feet per minute forcleaner steel. Such an adjustment to the apparatus may easily be made bysimply changing the setting on the Eagle Microflex Timer (27) to adifferent setting. A higher time setting on the dial thereof will causethe strip to run at a slower speed; a shorter timer setting to runfaster. These adjustments can be made while the slitting machine is inoperation. The sensitivity and response factor of the instant apparatusmay be varied by shifting the positions of the trips of the limitswitches 32 and 33 in relation to each other, by changing the diameterof the pick-up wheel 30, or by both such changes. And, by properadjustment the apparatus may be conditioned to hold the speed of thestrip 20 within a tolerance of one-tenth of a foot per minute.

Those portions of the control device constituted by the timer 27 andrelay 28 may be mounted in any suitable location, while the speedadjusting unit 29 is designed to be mounted on the front of a controlpanel in place of a rheostat control knob. Additional features of thisparticular part of the apparatus reside in its means for quicklychanging from automatic to manual control. Thus, when the selectorswitch 47 is moved to Manual the clutch solenoid 45 is de-energized, theclutch 43 is disengaged, and the rheostat 37 is conditioned for manualoperation through the shaft 39 by manually turning the knob 38. Also,when the selector switch 47 is turned to Manual the speed control unitis turned off.

Through this expedient, the unit may be conditioned for manualoperations and the motor coiler motor 18 may be gradually brought up tothe desired speed which will be maintained by the controller apparatusjust described. When the slitting machine approaches this desired speed,the selector switch is turned to Automatic and the controller brings itto the correct speed and holds it there.

As a further refinement, this unit can be equipped with limit switchesto provide high and low limits for the speed of the coiler motor 18.Further, the unit 29 may be provided with means to automatically returnthe rheostat 37 to its low limit setting each time the motor 18 isturned off. Such provision will assure that the slitting machine willalways be started at slow speed.

Although a preferred embodiment of the invention has been shown anddescribed, and its application in connection with the use of a steelslitting machine presented, it is obvious that the same is susceptibleof many other and different embodiments and applications. Thus, tomention only a few, the unit 29 could be used to operate a ReevesVariable Speed Transmission, a US. Varidrive Motor, the throttle of aninternal combustion engine, a steam engine, or a braking device, and thedevice whose speed is to be controlled could take the form of a belt,wheel, vehicle, elevator, etc. On pick-up head 30, the two switches 32and 33 could be replaced by a single switch actuated by a cam or ramp insuch a manner that it would be operated for /4 of a revolution. Thiswould eliminate the holding circuit through CRI-B. CRI would simply turnoff and on in conjunction with the switch. The functions of CR1 could behandled by a multi-poled switch that would be physically tripped by thecam or ramp described above. Insofar as these, and all othermodifications to which the invention is susceptible, fall within thescope of the appended claims they are considered covered as ifdescribed.

I claim:

1. In combination with a machine having an electric prime mover fordriving a roll to move a strip of material, a device for manually orautomatically adjusting the linear speed of said strip to a desiredrate, including:

(a) a rheostat comprising a rotatable shaft for controlling themagnitude of the electric current flowing to said prime mover, saidshaft when rotated in a first direction increasing the quantity of saidcurrent flowing to said prime mover to increase the rate of rotation ofsaid prime mover and roll, with said shaft when rotated in a seconddirection decreasing the quantity of said current flowing to said primemover to decrease the rate of rotation of said prime mover and roll;

(b) first means for manually rotating said shaft;

(c) a reversible electric motor that rotates in a first direction uponreceiving a first electric signal and in a second direction uponreceiving a second electric signal;

(0.) a clutch interposed between said shaft and motor to permit saidshaft to be rotated in either a first or second direction by said motor;

(e) a movable arm for moving said clutch to an engaging or disengagingposition;

(f) a solenoid, which when energized, moves said arm to place saidclutch in an engaging position to permit said shaft to be rotated bysaid motor;

(g) a selector switch, which when in a closed position, energizes saidsolenoid from a source of electric power to permit said shaft to bedriven by said motor, with said switch when in an open positionpermitting said first means to be used to manually rotate said shaft;

(h) a first normally open switch and a second normally closed switchspaced therefrom;

(i) a rotatable cam, which as it rotates sequentially and momentarily,closes said first switch and opens said second switch;

(j) second means for rotating said cam at a rate that is proportional tothe linear speed of said strip;

(k) an electrically operated timer which after actuation takes apredetermined period of time to reach a timed-out position, which periodis the same length of time as that required by said cam to close saidfirst switch and open said second switch when said strip is moving atsaid desired rate; and

(I) first and second normally open electrical circuits including holdingmeans, of which said first and second switches and said timer form apart, for sending said first and second signals to said motor, saidtimer being started when said cam closes said first switch, said firstcircuit being closed to send said first signal when said timer hasreached said timed-out position prior to opening of said second switchby said cam, which first signal continues to be sent until said camopens said second switch, with said second circuit being closed to sendsaid second signal when said cam opens said second switch prior to saidtimer reaching said timed-out position, with said second signalcontinuing to be sent until said timer reaches said timed-out position,and with neither said first nor second circuits being closed it said camopens said second switch concurrently with said timer as it reaches saidtimed-out position.

2. A device as defined in claim 1 which further includes relay means forholding said first circuit in a closed condition from the time saidtimer has reached said timedout position until said cam opens saidsecond switch.

3. A device as defined in claim 1 which further includes relay means forholding said second circuit in a closed condition from the time saidsecond switch is opened by said cam until said timer reaches saidtimedout position.

4. A device as defined in claim 1 wherein said second means comprises arubber-tired wheel that is in frictional contact with said strip androtated thereby.

5. A device as defined in claim 1 wherein said holding means includes acontrol relay, with relay means for holding said control relay in aclosed condition from the time said first switch is closed by said camuntil said second switch is opened by said cam.

No references cited.

ORIS L. RADER, Primary Examiner.

1. IN COMBINATION WITH A MACHINE HAVING AN ELECTRIC PRIME MOVER FORDRIVING A ROLL TO MOVE STRIP OF MATERIAL, A DEVICE FOR MANUALLY ORAUTOMATICALLY ADJUSTING THE LINEAR SPEED OF SAID STRIP TO A DESIREDRATE, INCLUDING: (A) A RHEOSTAT COMPRISING A ROTATABLE SHAFT FORCONTROLLING THE MAGNITUDE OF THE ELECTRIC CURRENT FLOWING TO SAID PRIMEMOVER, SAID SHAFT WHEN ROTATED IN A FIRST DIRECTION INCREASING THEQUANTITY OF SAID CURRENT FLOWING TO SAID PRIME MOVER TO INCREASE THERATE OF ROTATION OF SAID PRIME MOVER AND ROLL, WITH SAID SHAFT WHENROTATED IN A SECOND DIRECTION DECREASING THE QUANTITY OF SAID CURRENTFLOWING TO SAID PRIME MOVER TO DECREASE THE RATE OF ROTATION OF SAIDPRIME MOVER AND ROLL; (B) FIRST MEANS FOR MANUALLY ROTATING SAID SHAFT;(C) A REVERSIBLE ELECTRIC MOTOR THAT ROTATES IN A FIRST DIRECTION UPONRECEIVING A FIRST ELECTRIC SIGNAL AND IN A SECOND DIRECTION UPONRECEIVING A SECOND ELECTRIC SIGNAL; (D) A CLUTCH INTERPOSED BETWEEN SAIDSHAFT AND MOTOR TO PERMIT SAID SHAFT TO BE ROTATE DIN EITHER A FIRST ORSECOND DIRECTION BY SAID MOTOR; (E) A MOVABLE ARM FOR MOVING SAID CLUTCHTO AN ENGAGING OR DISENGAGING POSITION; (F) A SOLENOID, WHICH WHENENERGIZED, MOVES SAID ARM TO PLACE SAID CLUTCH IN AN ENGAGING POSITIONTO PERMIT SAID SHAFT TO BE ROTATED BY SAID MOTOR; (G) A SELECTOR SWITCH,WHICH WHEN IN A CLOSED POSITION, ENERGIZES SAID SOLENOID FROM A SOURCEOF ELECTRIC POWER TO PERMIT SAID SHAFT TO BE DRIVEN BY SAID MOTOR, WITHSAID SWITCH WHEN IN AN OPEN POSITION PERMITTING SAID FIRST MEANS TO BEUSED TO MANUALLY ROTATE SAID SHAFT; (H) A FIRST NORMALLY OPEN SWITCH ANDA SECOND NORMALLY CLOSED SWITCH SPACED THEREFROM; (I) A ROTATABLE CAM,WHICH AS IT ROTATES SEQENTIALLY AND MOMENTARILY, CLOSES SAID FIRSTSWITCH AND OPENS SAID SECOND SWITCH; (J) SECOND MEANS FOR ROTATING SAIDCAM AT A RATE THAT IS PROPORTIONAL TO THE LINEAR SPEED OF SAID STRIP;(K) AN ELECTRICALLY OPERATED TIMER WHICH AFTER ACTUATION TAKES APREDETERMINED PERIOD OF TIME TO REACH A "TIMED-OUT" POSITION, WHICHPERIOD IS THE SAME LENGTH OF TIME AS THAT REQUIRED BY SAID CAM TO CLOSESAID FIRST SWITCH AND OPEN SAID SECOND SWITCH WHEN SAID STRIP IS MOVINGAT SAID DESIRED RATE; AND (L) FIRST AND SECOND NORMALLY OPEN ELECTRICALCIRCUITS INCLUDING HOLDING MEANS, OF WHICH SAID FIRST AND SECONESWITCHES AND SAID TIMER FORM A PART, FOR SENDING SAID FIRST AND SECONDSIGNALS TO SAID MOTOR, SAID TIMER BEING STARTED WHEN SAID CAM CLOSES ANDFIRST SWITCH, SAID FIRST CIRCUIT BEING CLOSED TO SEND SAID FIRST SIGNALWHEN SAID TIMER HAS REACHED SAID "TIMED-OUT-" POSITION PRIOR TO OPENINGOF SAID SECOND SWITCH BY SAID CAM, WHICH FIRST SIGNAL CONTINUES TO BESENT UNTIL SAID CAM OPENS SAID SECOND SWITCH, WITH SAID SECOND CIRCUITBEING CLOSURE TO SEND SAID SECOND SIGNAL WHEN SAID CAM OPENS SAID SECONDSWITCH PRIOR TO SAID TIMER REACHING SAID "TIMED-OUT" POSITION, WITH SAIDSECOND SIGNAL CONTINUING TO BE SENT UNTIL SAID TIMER REACHES SAID"TIMED-OUT" POSITION, AND WITH NEITHER SAID FIRST NOR SECOND CIRCUITSBEING CLOSED IF SAID CAM OPENS SAID SECOND SWITCH CONCURRENTLY WITH SAIDTIMER AS IT REACHES SAID "TIMED-OUT" POSITION.